Improvement in pavements



R..DAVISON.

PAVEMENTS.

No.185,3OZ. latented Dec.12, 1876.

in? v N PETERS ROBERT DAVISON, OF-NO. 4 snorinnlrcn, HIGH srannr,ENGLAND.

IMPROVEMENTIN, F AVEMENT S.

Specification forming part of Letters Patent No. 185,302, dated December12, 1876; application filed a April 27,1876.;

To all whom may concern.-

Be it known that I, ROBERT DAVISON, of

and Ways, of which the following is a specification: i

This invention has for. its object the con-' struction of a paving ofgreat durability, with a minimum adhesion of wheel-surfaces, therebydiminishing friction and the powerrequired to draw a load, and at thesame time securingi ample provision for the foothold of animals; and theinvention consists in the adaptation and application to asphaltpavements of iron plates or frames, with projecting chilled iron studsor bearing-surfaces at suitable intervals, the spaces between them beingfilled in with asphalt, thereby producing a pavement of asphalt withslightly projecting chilled-iron studs or bearing-surfaces, adapted tosustain heavy traffic, and to give the requisite foothold for horses.The iron plates or frames for retaining the chilled studs orbearing-surfaces in position, as required, may be cast altogether iniron molds or chills, or in molds composed partly of iron and partly ofsand, the molds being constructed and arranged so as to produce castingswith suitable pieces or webs of metal for retaining and supporting thechillediron studs or bearing-surfaces. The said plates or frames may bevaried in size and thickness to suit the traffic, and it is intended toform the pavement by first laying a substratum of concrete, thencovering this bed with a thin lay of asphalt wherenecessary, andafterward laying the iron plates or frames evenly on the top thereof.Asphalt will then be run over the whole surface suffioient to fill upthe spaces in the plates or frames, and leaving the chillediron studs orbearing-surfaces flush with the surface of the asphalt, but which willslightly project therefrom on the shrinking of the asphalt during theprocess of cooling; or, if necessary, the asphalt may be pressed inorder to give the requisite projection to the studs. The asphaltemployed for filling in the interstices of the iron framing may consistof a mixture of natural rock, asphalt, chalk, or stone-dust,bituminousshale, or other approved materials, combined by the action of heat orotherwise.

The above-described system of paving may also be advantageously used forpassages, staircases, brewery-cellars, and the like floors of buildings,and other positions where great durability and, power to sustain traificare required, and it can be made ornamental by the introduction ofcastings of white vor yellow metal or other durable substance ormaterial.

Figure l is a plan or horizontal view" of a metal frame with. a numberof slightly-projeeting chilled-iron studs or bearing-surfaces,

with interstices to be filled in with asphalt or tained, as required, bycurved webs and basepla-te B B, leaving spaces 0 G to be filled in withasphalt D, in such a manner as to cover the whole surface of the road orway, with the exception of the studs or bearing-surfaces A" A, which areleft slightly projecting from the surface of the asphalt D, as shown inFigs. 2 and 3. In Fig. 3, E is the bed of concrete or other suffioientsubstratum adapted to constitute the foundation of the road or way, andF is a thin layer of bituminous material, which is laid so as to presentan even surface upon which to bed the metal frame carrying theprojecting studs or bearing-surfaces, forming the hard unyielding anddurable portion of the road or way. These metal frames are laid on andpressed down onto the bituminous material F while heated and yielding,so as to form a solid bearing for the metal frame-work.

The frames are, by preference, made of castiron run into eitherstationary or. movable molds, made by hand or machine, arranged so as tochill and thereby harden the parts of the frames which, when in use,will be exposed to abrasion, and the frames and such parts thereof aremade of such sizes, weights, (varying for roads from fifty to onehundred and fifty pounds or upward per square yard,) :and

shapes as may be most suitable for the conditions of the road or way tobe formed. These plates or frames are formed of a perforated base plate,with the holes or perforations arranged regularly in rows, and of such asize as to leave between them sufficient bearingsurface of metal tosupport the weight of the vehicles passing over the road or way.

Upon the parts where the webs B B intersect there are projecting pieces,the faces of which form the projectingstuds or bearingsurfaces A A,which constitute the metallic portion of the surface of the improvedroad or way. The molds in which these plates or frames are cast may bemade of sand in the usual manner, or partly of sand and partly of iron,so that the surfaces of the projecting pieces above referred to may bechilled by the melted iron flowing upon an iron surface, or the moldsmay be of fire-clay, or fire-clay and iron, or wholly of iron. In somecases the plates or frames may be made of hard or white iron, so as toproduce hard castings without chilling. These plates or frames arefilled in with asphalt or other suitable material (intended to form thesurface of the road or way in the spaces between the said projectingpieces) to within a small distance of the studs or bearing-surfaces A A,so as to leave them slightly projecting from the general-surface of.

the filling-in material, thereby forming a good foothold for horses, andpresenting a diminished resistance to traction.

From the foregoing description it will be evident that the essentialfeature of the invention consists in forming the surface of roads orways partly of a comparatively yielding material, such as asphalt,impervious to water, and with minimum liability to abrasion, and partlyof a hard unyielding and durable material, such as chilled cast-iron.

By means of this combination is obtained a durable: and even roadsurface, suitable for all kinds of traffic, with a suflicient amount ofroughness to give foothold for horses and other animals when drawingloads, and reduce the resistance of traction, thereby securing theadvantages of asphalt paving while avoiding the slipperiness inseparablefrom the ordinary construction thereof.

I claim as my invention- A pavement constructed of ascries of ironframes, having a number of studs or bearingsurfaces, A, formed with thecurved webs and base-plates B, and bearing spaces 0, to receive theasphalt, and the whole adapted to a foundation, F, substantially asdescribed.

ROBT. DAVISON.

Witnesses: I

WILLIAM SPENGE, ALFRED H. JONES.

